Appropriateness of Empirical Fluoroquinolones Therapy in Patients Infected with Escherichia coli, Klebsiella pneumoniae, or Pseudomonas aeruginosa: The Importance of the CLSI Breakpoints Revision

Ying Wang,1 Xinping Zhang,1 Xuemei Wang,1 Xiaoquan Lai2 1School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, People’s Republic of China; 2Department of Nosocomial Infection Management, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, People’s Republic of ChinaCorrespondence: Xinping ZhangSchool of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of ChinaTel +86 133 4995 0095Email xpzhang602@hust.edu.cnPurpose: Empirical antibiotic therapy should follow the local bacterial susceptibility, and the breakpoints revisions of the antimicrobial susceptibility testing can reflect the changes in the antimicrobial susceptibility of bacteria. This study aimed to analyze whether the changes in the antimicrobial susceptibility to antibiotics caused by the breakpoint revision will affect the empirical antibiotic therapy and its appropriateness.Patients and Methods: A retrospective study was conducted among 831 hospitalized patients infected by Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa from April 10, 2018, to April 11, 2020. We evaluated the appropriateness of empirical therapy based on the antimicrobial susceptibility testing results. The rate of empirical use and appropriateness of fluoroquinolones was calculated, and logistic regression was used to analyze influencing factors of empirical use of fluoroquinolones.Results: The susceptibility rate of the three bacteria to levofloxacin (50.78% vs 32.06%) and ciprofloxacin (48.45% vs 21.90%) was decreased (P< 0.001), while the resistance rate to levofloxacin (45.74% vs 58.73%) and ciprofloxacin (46.90% vs 66.67%) was increased (P< 0.001) after the breakpoints revision. The empirical usage rate of fluoroquinolones in patients infected with Escherichia coli, Klebsiella pneumoniae, or Pse